קָפָא qâphâʼ (H7087)

to shrink, i.e. thicken (as unracked wine, curdled milk, clouded sky, frozen water)

v 1) to thicken, condense, congeal, settle, become dense 1a) (Qal) to be condensed 1a1) thickening (participle) 1b) (Hiphil) to cause to curdle n m 2) congelation

a primitive root;